Reference may be made to the following U.S. patents: 3,509,339; 3,509,341; 3,578,960; and 3,717,762. In presently available diagnostic apparatus, discrete portions of radioactive particle emitting samples are analyzed by detecting and measuring the radioactive sample counts over a long time interval. There are also presently available scanning type devices which are used to scan portions of the human body and locate the distribution of radioactive material previously injected. The above listed U.S. patents illustrate embodiments of each type.
While the aforementioned prior art is suitable for the purposes indicated, it is desired to simplify and to make more compact and reliable the rather large, multiple components required by such prior art systems, particularly when it is desired to count the radioactive particles from multiple samples. In the detecting portion of the prior art, visible light emitting crystals are used, such as sodium iodide crystals which emit visible light when impinged by gamma radiation. Various forms of collimator members formed of radioactive opaque material are used to channel the emitted radiation to the crystal and to otherwise prevent undesired or spurious radiation sources from impinging on the sodium iodide crystal. The emitted visible light from the sodium iodide crystal is then converted and amplified by a photomultiplier tube to provide the corresponding electrical signals relating to the detected count sample. Such prior art diagnostic systems are rather large and particularly cumbersome.
Also, in instances where there are a number of samples to be counted, it is desired to be able to obtain accumulated sample count over repeated predetermined time intervals for each sample, rather than completing the measuring of sample counts for each sample before beginning measurement of the next sample. In the case of gamma radiation sample counting for instance, as an illustration, let us assume it normally requires approximately one minute to accumulate about ten thousand sample counts in order to provide approximately a 1% sample count precision. Thus, in this illustration, if 100 samples were being analyzed on a sequential, serial analysis procedure, the sample count for 60 samples would be obtained in about one hour, whereas no sample count information would be obtained or available on the remaining 40 samples during the first hour. It is therefore desired to provide a simplified multiple sample analysis or diagnostic system wherein sample count data can be rapidly and reliably obtained for each of the samples. In some instances it is also preferred to display or print the preliminary, periodic, accumulated sample count as obtained so as to provide a periodic check on the system operation.